Fluid lift



Oct. 21, 1941. M. P. BURKE 2,259,949

' FLUID LIFT v Filed April 2l, 1938 2`Sheets-Sheet l ATTORNEY- oct. 21, 1941. M. R BURKE 2,259,949

FLUID LIFT I Filed April 2l, 1938 2 Sheets-Sheet 2 r4- fzg, 2

'1931, entitled Gas lift means.

to'fthe perforated scr-een II.

Patented Oct. 21, 1941 UNITED STATES PATENTr OFFICE FLUID mir Mark P. Burke, Long Beach, Calif. Application April 21, 1938, Serial No. 203,451 1s claims. g(o1. 10s- 234) This invention relates to a deep Well pumping mechanism, and particularly pertains to a fluid lift of the general type shown in U. S. Letters Patent No. 1,827,066 issued to me October 13,

Y In pumping a liquid from a well by the use 0f 'a fluid underpressure, such as gas, it is desirable toprovide means for alternately allowingliquid to accumulate in a well to a desired depth and then to introduce gas under pressure to lift the accumulated quantity of liquid irrespective of the degree of submergence of the lower end of the -flow pipe within the accumulated liquid of the well.

It is the principal object ofthe present invention to provide a simple valve mechanism which may be connected with the flow pipe at.

the lower end of the'well, Vwhich will act under 'pressure to direct said fluid against and beneath an accumulated quantity of liquid to elevate this act automatically to interrupt the ow period when a predetermined accumulated quantity of liquid has been elevated through the flow pipe.

" vThe present invention contemplates the pro- Y'quantity of liquid through the ow pipe, and to 20 vision o`f a flow pipe adapted to be lowered into m5 la' well casing and carrying a packer which en- 'gages the casing and packs off a pumping cham- -ber at the bottom of a well, said flow pipe also carrying a valve mechanism which acts autofrom a well.

VThe invention is illustrated by way of example 'in the accompanying drawings in which:

-matically due to changes in equilibrium of gas *3930 and a liquid to intermittently pump slugs of liquid Figure 1 is a fragmentary view in section and K:35

elevation showing the application of the present vinvention to a Well. l i Fig. 2 is an enlarged view in centrallongitudinalsection showing the automatic intermitter valve in its normal closed position. l

Fig. 3 is a View similar to Fig. '2, 'showing the -intermitter valve opened. Fig. 4 is a view in transverse section `through the intermitter valve structure as seenon the line 4 4 of Fig. 3 andas viewed in the direction 'of' the arrows. y

' Referring more particularly to the drawings, Il)

well casing and terminates within or adjacent The ow pipe'is sealed in at the top of the casing I I l by a suitable instrumentality I3; a gas inlet pipe I4 communirests.

above the level of the ground and is in communication with suitable gas pressurey flow and regulating means in a partv of the present invention. Y

Carried upon the flow pipe I2 and positioned at a suitablevdepth in the well is a casing packer I5, which forms a seal in the well and creates a lower chamber I6 within which Vliquid accumulates and an upper chamber I'I, through which gas may ow downwardly within the 'casing I0 and around the flow pipe I2 for aV purpose tobe hereinafter described. Mounted Vwithinvthe flow- Dpe I2 and here shown asvbeing disposed at a ,level above the level ofthe packer I5 is an automatic intermitter valve I8. By reference to Figs. 2 and 3 lit will be seen that this valve includes an outer tubular valve housing I9 having an enlarged upper portion 29 which ts within the flow pipe I2 and is here shown as being welded in position. A downwardly projecting portion 2I `of the valve housing I9'is of reduced diameterl as compared with theY upper portion 20 and provides an annular fluid space 22 in the upper end of a liquid chamber 23.

Extending through the upper portion 2D of the housing I9 is a plurality of longitudinally aligned `ducts 24, which establish uninterrupted communication between the chamber 23 and the length of flow pipe I2 above the valve I8. The upper enlarged end 20 of the housing I9 is formed with a central bore 25, which terminates in a square shoulder 26 and an inclined valve face 2'I.

-The lower portion 2| of the housing I9 is formed with a bore 28, which is a continuation of a central aligned passageway through the housing and which bore is of reduced diameter as compared with the upper communicating bore 25. The

-upper end of the bore 29 terminates with the downwardly and inwardly inclined valve face 21 and the lower end of the bore terminates with `an internally threaded portion 29, which receives a threaded adjusting plug 30.

I 'he plug 3U provides a'seat for a compression spring 3|'. Whichis positioned within the bore 28 and upon which a balanced valve element 32 This valve element has a lower cylindrical portion 33 which ts into the bore 28 with a sliding fit. A plurality of sealing grooves 34 1s formed around the outer circumference of the portion 33 and tends to form a liquid seal between this lcircumference and the bore 28.

vcates with4 the interior of the casing II) at apoint 55 'to abut against the face 21 of the valve housing and to form a fluid seal therewith when so positioned. The upper shoulder 31 of the enlarged valve portion 35 is oppositely tapered from the shoulder 36 and abuts against an inclined valve face 38 of a valve seat sleeve 39. This valve seat sleeve has a central bore 49 extending upwardly therethrough which is in longitudinal alignment with and the same diameter as the bore 28 in the lower extension 2| of the valve housing I9. The upper end of the bore 48 has an enlarged undercut recess 4I therein, which provides an overhanging downwardly and outwardly inclined valve face 42, terminating in an upper central opening 43. An inclined valve face 44 is formed on the upper end of the valve element 321 and abuts against the face 42 when the shoulder 31 of the valve portion 35 abuts against the face 38 of the valve seat 39.

Interposed between the shoulder 26 -of the valve housing and the lower end of the valve seat 39 is a spacing ring 45, which positions the valve `faces 21 and 38 in such a spaced relation to each other as to permit a predetermined amount of longitudinal movement of the valve element 32 within the housing I9 while the shoulder 31 moves rfrom an abutting position against the face 38 `until the shoulder 35 seatsagainst the face 21.

, Y As shown particularly in Fig. 4 of the drawings a plurality of radially disposed ducts 46 are formed through the wall of the ow pipe I2, the upper portion 20 of the housing i9 and the wall uof the valve seat 39. By reference to Figs. 2 and 3 it will be seen that these ducts 46 establish communication between the gas chamber I1 and the recess 4| formed within thevalve seat 39 and `that when the movable valve `element 32 is in within the plug 33. Fluid can, therefore, fill the space within the bore from the plug I9 upwardly and into the passageway 41 within the valve element. Formed through the plug I9' is a passageway 48 Vwhich receives a check valve structure 48; 'I-hisstructure will permit an outflowof fluid from the bore` 28 and the passageway 41 within the valve element Vwhile preventing an Vinflow of fluid through the valve.`

In operation of the present invention a -suitable iiuid pressure regulating means is connected with the pipe I4 and is interposed between this pipe and a suitable source of fluid under pressure. The flow pipe I2 is lowered into the well with its packer I and is set in position. MountedA adjacent to the lower end of the flow tubeand carried thereby is a standing valve 49 which permits liquid to ,enter the flow tube but not to exit therefrom. The spring 3| of the valve has .been

adjusted by the adjusting nut 39, so that the valve element 82 will be held in its uppermost `position and with a luid seal occurring between -thefaces 42' and 44 and the faces 31 and y38e. When the packer I5 has been properly set in the well casing I2 the lower liquid chamber I6 will besealed offat the bottom ofthe well casing and the gas chamber I1 will be sealed off in `area betwee the packerandthe top of the well.

When Ya predetermined level of liquid has been reached gas under pressure is deliveredto the casing I0 through the pipe I4. This gas passes downwardly within the chamber I1 and will be forced inwardly through the radial passageways 46 to the recess 4| within the valve seat 39. The further flow of the gas will be interrupted due to the fact that the valve 32 is in its closed position. When, however, the accumulated column of liquid within the length of flow pipe I2 above the intermitter valve structure is of suflicient head to exert a pressure against the end face of the valvey member 32, through the central opening 59 in the top of the valve seat structure 3.9, to overcome the force of the spring 3| the valve element 32 will move downwardly to its opened position, at which time the shoulder 3G `on the valve element will abut against the face 21 in the valve housing and seal off the bore 28 from the ,gas under pressure, which is being delivered through the chamber l1. This gas will pass through the radial passageways 46 and the recess 4I into the central opening 53 of the memgber`,3 9 and will then be disposed beneath the ac- -cumulated column of liquid which is within the length of flow pipe above the'valve structure.`

Attention is directed to the fact that the volume of gas delivered to the valve structure is .such `as toinsure that the gas will not aerate the liquid, but will move beneath it and lift the accumulated body of oil as one mass. This .lifting action will continue until the weight of the liquid mass'imposed upon the valve element 32 has diminished to a point where the spring 3| will move the valve element 32 to its upper and closed position. The `ow of gas will thus be interrupted and another volume of oil may then build up within Vthe flow pipe I2 until its weight is .suflicient to open the valve 32 again. Y

Attention is directed to the fact that durin the period following the time when the slug of liquid has been forced from the well the fluid pressure of the operating fluid will have been reduced by the escape of the uid through the flow pipe I2' and the valve will have been closed. ,At this time and before the liquid to be pumped has again entered the liquid chamber 23, the fluid .pressure around the valve structure and within -the bore 28 and the passageway 41 will be reduced substantially to atmospheric pressure. The check valve 49 mounted at the bottom of the bore 28 will then permit any excessive iiuid pres- :sure within the bore 28 to equalize with the pressure surrounding the valve since the valve 48 nmay open to relieve the pressure within the valve. As hereprovided, the closed chamber 28 with its equalizing check valve 48 makes it possible to establish a predetermined resistanceV against the movable valve element 32 by the spring 3| and .the adjusting nut 3U. It will be recognized that vtheA spring 3| is of a, strength to support the weight of a column of fluid accumulated in the tubing I2 and above the' valve element. Thus, for example, if the determined weight of an accumulated column of liquid was equal to 300 pounds per square inch against the movable ele- 'ment 32 through the opening 43 the strength of the spring 3| would of necessity be more than 300 lpounds and would be set by adjustable nut 29 *tov yield at 300 pounds. In the course of operation of the movable valve element 32 fluid ymay leak around the valve element vand accumulate :within the bore 2'8 compressing the air in bore 28 and passageway 41. For this reason the port 48 and thev check valve 48 have been mounted at .the lower end of the bore 28. It will be seen that 7the'port48 `and the check va'lve 48' will allow the compressed air in the-chamber 28 and the passageway 41 to exhaust any accumulation of fluid that may have leaked thereinto during the cycle of operation of the valve element 32, and that this exhaust will `take place -at the low point in the pumping cycle so that there will not be undesired pressure resistance against the movable element `32,-making it possible to set the spring 3| for a 4predetermined pressure and also prevent valve element 32 from becoming fluid locked. At the low'point in the pumping cycle the entrapped and compressed fluid within bore 28 will be exhausted until the pressure within the bore 28 substantially equals the pressure outside of valve 48 at which time the valve 48 will close. the port 48 and check valve 48 allow the chamber 28 and passageway 41 to exhaust any accumulation of fluid that may have leaked thereintol during each cycle of operation of the valve element 32. When the valve element 32 is thereafter forced to its opened position by the weight of the accumulated liquid column in flow pipe I2' the pressure operating fluid will be again directed beneath and against the liquid column and the end of the valve which is exposed through the central opening 43 of the housing. The valve element 32 will then instantly move to its opened position. This will simultaneously act to move the shoulders 21 and 36 of the housing and valve,

respectively, to abutting positions, as shown in 1 Fig. 3 of the drawings, so that the bore 28 and the space 41 will be sealed against the effect or action of 'iiuid under pressure which might otherwise be forced downwardly around the upper portion of the valve stem and in the upper bore 40 while the shoulders 31 and 38 are separated; When the valve is opened the valve element 32 has exposed a larger area of the upper end of the valve element as it has moved fromits seat 42,-an excess pressure will beexerted upon the valve element to retain it in its opened position until the slug of liquid hasY been ejected from the well. `When the valve is closed, as shown in Fig. 2 of the drawings, the movable element 32 is seated and fluid pressure exerted through the ducts 46 is neutralized against the sides of the movable element. A column of liquid accumulates within the flow tube to impose a hydrostatic head upon the exposed end of the movable element 32. This hydrostatic head is supported by the movable element 32 and the spring 3l until the column of fluid provides al pressure sufcient to overcome the pressure of the spring, at which time the movable element 32 will be lowered so that the fluid pressure through ducts 46 may be directed upwardly over the end of the movableelement 32 and through the opening 43 to a point beneath the slug of liquid which has accumulated in the pipe l2. While this action takes place pressure will be at a maximum, and it may occur that iluid may be forced downwardly around the movable element 32 to fill the bore`28 and the bore 41. At the end of the pumping cycle when the slug has been discharged from the'well u'id pressure will be at a minimum, and in'the event the accumulated liquidV within the bore 28 and the bore l41 exerts a pressure greater than the pressure of the iluids within which the valve structure is enveloped the check valve 48' will open to permit this fluid to be discharged. Instantly, however, when the pressure on the outside of the valve 48 exceeds the pressure on the inside of thevalve structure the valve 48' will close. This'makes it possible for a completely submerged flow valve to be operated in a tubing andfto insure that the It will be seen that ow valve will not at any time become uid locked. 4 l Attention is directed to the fact that this invention is particularly novel in that it provides a' valve structure which Will-'function under the action `produced by the pressure created, a pressure operating fluid and a denite column of liquid within which the pump is submerged and by which action a slug of liquid Will be ejected from the Well. As has been previously disclosed,

- this is brought about by the balancing and overbalancing of pressures which exist between a constant uid pressure and the pressure of a predetermined liquid column as controlled'and regulated by the valve structure here disclosed.

It will thus be seen that the structure here disclosed provides means including a single string of pipe which may be introduced into a well casing to a selected depth and by which a continuous supply of a fluid under pressure may be intermittently released to elevate massesv of oil to the topof the well by an automatic operation Vdepending "exclusivelyupon the accumulation of a predeterminedquantity of oil within the flow pipe and-without reference to any timing of the gas supply delivery or the valve actuation.V

While I have shown the preferred form of my invention as now known to me, it will be understood that various :changes may be made in the combination, construction and. arrangement of parts by those skilled inthe art without departing from the spirit of the invention as shown.

Having thus described my invention, what I claimand desire to secure by Letters Patent is:

l. A fluid liftapparatusV for wells comprising'a casing,` a flow tubeextending downwardly therein, a foot valve in the bottom of said owtube, said lowerend of the" flow tube being submerged in the'liquid of the well,'means for packing off the space lbetween the casing and the flow tube to forma liquid pressure chamber at the bottom ofthe weiland a pressure fluid space thereabove, avalve structure disposed within the iiow tube at a level above the packing means, said valve structure including a fixed element having liquid ports therefrom and through which liquid may freely flow from theportion of the flow tube below the valve into the portion of flow tube thereabove and other portsin saidvalve element through which uid under pressure from'the casing may flow into the portion of flow tube above the valve when the valve is open, a Valve element located within the valve structure and normally closing the ports for the fluid under pressure and moving to an open position when a predetermined head of liquid hasV accumulated within the flow tube above thevalve and `beneath which leakage liquid collects within the valve structure and means acting at the' low pressure point in the pumping cycle to clear the valve 'structure of fluid and to prevent the valve frombecoming fluid locked.

" 2. A iluidlift' apparatus for wellsA comprising a casing, a 'flow tube' extending downwardly therein, afoot valve inthe bottom of said flow tube, said'lower end'mc the flow tube being submerged in theY liquid of thefwell', means for packing ofi` the space between the casing and the iiow tube to form a liquid pressure chamber at the bottom of the well and a pressure fluid space thereabove, a valve structure'disposed within the ow tube at a level above the packing means, said-valve structure including'aY xed element having liquid ports therefrom and through which liquidvmay freely flow from the portion of the flow tube below the valve into theportion of flow tube thereabove and other ports in said valve element through which fluid under pressure from `the casing may ow into the portion of flow tube above the valve, a valve element located within y.the valve structure and normally closing the ports for the fluid under pressure and moving to an open position when a predetermined head of liquid has accumulated within the flow tube -.above the valve and beneath which leakage liquid collects within the valve structure, means acting within the valve structure at the low pressure point in the pumping cycle to vent fluid from the structure and to prevent the valve from becoming uid locked, and yieldable adjustable means normally resisting the opening of the valve until a predetermined liquid column has accumulated thereabove.

3. A fluid lift apparatus for wells comprising a casing, a flow tube extending downwardly therein, a foot valve in the bottom of said flow tube, said lower end of the flow tube being submerged in the liquid of the well, means for packing off the space between the casing and the flow tube to form a liquid pressure chamber at the bottom of the Well and a pressure fluid space thereabove, a valve structure .disposed within the flow tube at a level above the packing means, said valve structure including a fixed element having liquid ports therefrom and through which liquid may freely flow from the portion of the flow tube below the valve into the portion of flow tube thereabove and other ports in said valve element through which fluid under pressure from the casing may iiow into the portion of flow tube above the valve, a valve element located within the valve structure and normally closing the ports for the fluid under pressure and moving to an open position when a predetermined head of liquid hasaccumulated within the flow tube above the valve and beneath which leakage liquid collects within the valve structure, means acting within the valve structure at the low pressure point in the pumping cycle to vent uid from the structure and to prevent the valve from becoming fluid locked, yieldable adjustable means normally resisting the opening of the valve until a predetermined liquid column has accumulated thereabove, and means forming a part of the valve whereby the area of the pressure surface exposed to the head of liquid within the tube will be increased when the valve opens to thus tend to maintain the valve in an opened position' during the pumping period.

4. In a fluid lift for wells, the combination of a chamber sealed off at the bottom of a well and submerged within the liquid of the well, a flow tube extending into said chamber, a foot valve in said ow tube, a valve structure disposed in the flow tube at a depth lower than the level of liquid within a well, means incorporated in said valve structure for permitting a continuous flow of liquid to flow upwardly through the flow tube 'and around the valve, means for introducing a fluid under pressure into the valve structure and whereby said fluid may be delivered beneath the column of liquid accumulated within the ow tube above the valve structure, a valve element located within the valve structure and normally preventing the flow of said fluid under pressure and acting to alternately open and close as affected'by variation in the accumulation of liquid within the flow tube and above the valve and beneath which valve leakage fluid may be entrapped prevent a greater ilud pressure within the valve 4structure than prevailing Within the tube;

5. In a fluid lift for wells, the combination yof a chamber'sealed off at the bottom of a well and submerged within the liquid of the well, a ow tube extending into said chamber, a foot valve in said flow tube, a valve structure disposed in the flow tube at a depth lower than the level of liquid within a well, means incorporated in said valve structure for permitting a continuous flow of liquid to flow upwardly through the flow tube and around the valve, means for introducing a fluid under pressure into the valve structure and whereby said fluid may be delivered beneath the column of liquid accumulated within the flow tube above the valve structure, a valve element located within the valve structure and normally preventing the iiow of said fluid under pressure and acting to alternately open and close as affected by variation in the accumulation of liquid within the flow tube and above the valve and beneath which leakage liquid collects within the valve structure, means incorporated within said valve structure for normally'establishing a fluid pressure within the valve which is not in excess .of-the fluidpressure within the flow tube, and means whereby the Valve will be over-balanced by the fluid when it is open. Y

6. In a fluid lift for wells, the combination of a chambersealed 01T atthe bottom of a :Well and submerged Within the liquid of the well, a ow tube extending into said chamber, a foot valve in said flow tube, a Valve structure disposed in the flow tube at a depth lower than the level of liquid withina well, means incorporated in said valve structure for permitting a continuous iiow .of liquid to ow upwardly through the flow tube and around the valve, means for introducing a fluid under pressure'into the valve structure and whereby said fluid may be delivered beneath the column of liquid accumulated within the iiow tube above the valve structure, a valve element located within the valve structure and normally preventing the flow of said fluid under pressure and acting to alternately open and close as affected by variation in the accumulation of liquid within the flow tube and above the valve and beneath which leakage liquid collects within the valve structure, means incorporated within said valve structure for normally establishing a fluid pressure within the valve which is not in excess of the fluid pressure within the flow tube, means c whereby the valve will be over-balanced by the and lmeans acting at the low point in the pumping cycle to establish equilibrium in iiuid pressure to fluid when it is open, and spring means yieldably holding the valve in its lclosed position.

7. A iiuid lift structure for wells comprising a vclosed chamber adaptedto be submerged within the liquid of a well, a conduit through which a column of liquid may be carried from said closed chamber, means packing off the conduit against the wall of the well, a conduit conducting fluid under pressure to said lcolumn of liquid adjacent the bottom thereof, a valve element located within the structure establishing and interrupting the iiow of said pressure fluid into said conduit, said valve element having Ymovable means therein upon which the weight of the .column of liquid will .be `imposed and by which weight only the valve will be opened when a predetermined hydrostatic ,head of liquid occurs thereabove, and means acting at the low* point in the pumping cycle to reduce fluid pressure Within the valve structure to a degree equal to the fluid pressure within the ilow tube.

8. A fluid lift structure for wells comprising a closed chamber adapted'to be. submerged within the. liquid of a well, a conduit through which `a column of liquid maybe carried from said closed chamber, means packing off the conduit against the wallof the Well, a conduit conducting vfluid under pressure to said column of liquid adjacent the bottom thereof, a valve element-located within the structure establishing and interrupting the ilow ofvsaidpressure fluid into said conduit, said valve element having movable means therein upon-fwhich the weight of the column of liquid will be-imposed and by which weight only the valve will be opened when a predetermined hydrostatic head of liquid occurs thereabove, means for establishing a predetermined resistance to the opening of said valve, and means acting at the low point in the pumping cycle to reduce fluid pressurewithin the valve structure to adegree equal to the fluid pressure within the flow tube.r

L 9, A fluid lift structure for wells oomprisinga closed chamber adapted to be submerged within the liquid of a Well, a conduit through which a column of liquid may be carried from said closed chamber, a conduit conducting fluid under pressure to said column of liquid adjacent the bottom thereof, a valve element located within the structure A:establishing and interrupting the now of said pressure fluid into said conduit, said valve element having movable means -therein upon which the weight of thecolumn ofliquid will be imposed and by which weight the valve will be opened whenv a1 predetermined hydrostatic head of liquid occurs thereabove and beneath which leakage liquid collects within the valve structure, and means for normally Yestablishing a fluid pressure within the valve structure as low as the fluid pressure within the flow tube andwhereby when the valve is opened it lwill be over-*balanced so as to be temporarily held in its opened position.

l0. A fluid lift apparatus for wells comprising' v forming a liquid pressure chamber therebelow and a pressure fluid chamber thereabove, a valve structure mounted in said ow tube above said packing means, said valve structure including a fixed element having ports for the passage of fluid from said lower chamber into a portion of said :dow tube above said valve structure, Walls forming passageways in said valve structure communicating with said pressure fluid chamber whereby fluid under pressure may flow into the portion of the flow tube above said valve structure, a valve element located within the Valve structure and freely mounted in said valve structure and normally closing said passageways and beneath which leakage liquid collects within the valve structure, said valve element beingadapted to move to an open position when a predetermined head of liquid has accumulated in said flow tube above said valve element, and means for balancing said valve element against fluid pressure by maintaining a fluid pressure within the valve structure in equilibrium with the iluid pressure in the flow tube.

1l. A fluid lift structure for wells including a closed chamber adapted to be submerged in the liquid of a well, a ilow tube extending downwardly into said chamber, a standing valve in said tube permitting only inflow of liquid from said chamber thereinto, a Valve structure Vmounted in said 110W tube, walls forming parts in said valve structure permittinggan'uninterrupted passage of a column ofllquidfromsaid chamber to said flow tube, walls forming a plurality of passageways in said valve ystructure adapted for the passage of a fluid under pressure to said flow tube above said valvemstructure, means for delivering fluidgunder pressure to said flow tube, a valve element located within thevalvestructure and normally interrupting Athe flow of fluid under pressureand acting under a predetermined Weight of a column of liquid within the ow pipe to open and permit entry vof fluid under pressure to said flow pipe belovv -,s aid column of liquid to lift the same and beneath which :leakage liquid collects Within the valve ystructure iand. means for balancing said valve element against fluid pressure by maintaining afuid pressure within the valve structure in equilibrium with the, fluid pressure in the ow Tailles@Y l e. Y

l2. A uid lift structure for wells comprising a closed .chamberradapted to be submerged Within the liquidfof a well, aflowtube extending downwardly into saidY chamber, a check valve therein permitting. inflow oflliquid from said chamber to the iiowwtube only, `arvalve structure within the flow tube :and disposed vbelow the level at which liquid will accumulate in the flow tube, said valve structurebeing formed with ports permitting an uninterrupted rise of a column of liquid through the valve structure andinto the flow tube, means vfor delivering a fluid under pressure to said valve structure, arvalve element normally interrupting the flow of uidunder pressure and acting under theweight of a predetermined column of liquid within the flow. pipe to open and to permit the entry of gas to the-flow pipe beneath said column ofhliquid to lift the same, walls forming a chamber -in said'- valve structure adapted for the accumulation of fluid seeping thereinto, and means forexhausting the fluid-from said chamber duringth low. pressure period in each cycle of operationv of said valve element.

a closed chamber adapted to be submerged within the liquid of a well, a flow tube extending downwardly into said chamber, a check valve therein permitting inflow of liquid from said chamber to the flow tube only, a valve structure Within the now tube and disposed below the level at which liquid will accumulate in the flow tube, said valve structure being formed with ports permitting an uninterrupted rise of a column of liquid through the valve structure and into the flow tube, means for delivering a fluid under pressure to said valve structure, a Valve element normally interrupting the flow of uid under pressure and acting under the weight of a predetermined column of liquid within the flow pipe to open and to permit the entry of gas to the flow pipe beneath said column of liquid to lift the same, Walls forming a chamber in said valve structure, means for sealing said chamber, and means for exhausting the seepage fluid from said chamber.

14. In a device of the character described, a valve structure including a movable valve element having a downwardly projecting portion, ment having a downwardly projecting portion a valve body having an enclosed chamber into which said projecting portion of said valve element moves and whereby av fluid pressure is prevented from being exerted against the projecting portion of said valve element within the enclosed chamber and within which chamber uid which has leaked around the valve element may be entrapped, a flow tube through which the fluid may 13. A fluid lift structure for Wells comprising flow and Within which said valve body is disposed, means for sealing said chamber while iiuid is being forced through said ow tube, and means for exhausting accumulated liquid from said chamber and into said tube.

l5. In a device of the character described, a valve structure including a Valve body having an enclosed chamber, a valve element mounted for longitudinal movement in said chamber and Within which chamber leakage fluid from around the valve element may pass and be entrapped, means for preventing a fluid pressure from being exerted against said valve element in said chamber, a flow tube Within which said valve body is disposed and through and around which fluid may flow, means for sealing said chamber While liquid is being forced through said flow tube, and means for exhausting accumulated leakage liquid that has seeped within said chamber While the liquid Wasv flowing. f

yloiIn a device of the character described, a valve structure' including a movable valve ele ment having upper and lower projecting` portions, a valve body having upper and lower chambers into which the projecting portions' of said va-lve element are adaptedA to-move and into which lower chamber leakage ui'd may be entrapped, a flow tube through Whichv uid may flow, walls forming a plurality of ports insaid valve body through whichv an uninterrupted flow ofA uidfrom said flow tube may pass, walls forming a'plurality of passageway's insaid valve body adapted for the passage of a compressible uid to said upper chamber for elevating a column of liquid in said flow' tube above said valve Structure, means for sealing said lower chamber While' liquid is being forced through the iovv tube and from the well, and means for exhausting accumulatedv leakage liquid Yfrom sa-idflower chamber, which liquid has entered said chamber whilethe liquid was iiowing.

17,. In a device of the character described,l a valve structure, said valve structure including' a heu-sing, a movable valve element? meren; co-

operating With thehousing to form a fluid cham-jl ber between the valve element and one end of the housing an inlet port opened by the valve to admit pressure fluid into said housing, a tubing within V'Which said housing is positioned and aroundwhichevvell uid may flow to accumulate a slug of liquid thereabove Within the tubing, a valved outlet establishing communication between the housing chamber and thev tubing, whereby the pressure of 4fluid within'the chamber vwill exhaust after the slug of liquid has been forced from the Well and Will permit the fluid With-in the chamber and Within the tubing to equalize in pressure at a point in the flow cycle, after the slug of liquid has been discharged from the tube.

18. In a device of the character described', a flow tube, a Well casing enclosing the saine, a valve structure disposed Within said tube and around which Well fluids may rise to form a column of fluids lWithin the tube, said valve structure in'- cluding' a housing, a movable valve element upon the end of which the Well fluids accumulate; yieldablemeans resisting the' hydrostatic head of said fluids until the column has reached a prede terminedheight, ducts delivering a fluid under pressure through the valve housing from the Well casing, said fluid being released into the flow tube when the column reaches a predetermined heightg'whe'reby the Well fluids will be ejected from the 'flow tube asr a slug of liquid; the lower end of the valve housing entrapping iiuids passing around the valve and being normal-ly closed,-

- a'ndmeans acting at the low pressure point in the pumping cycle to permit the entrapped fluids at a Vpressure in lexcess of the pressure in thel well tol be relievedfrom the' closed end of the valve housing, whereby fluid-locking of rthev Valve is prevented.

MARK P. BURKE. 

